William steebs



W.- STEERS.

EXTENSION BIT.

(No Model.)

Patentd Apr. 1, 1884.

Fig. 2.

N2 PETEFIS. Flmwuibognpher. wmvigwk a c.

UNITED STATES PATENT OFFICE.

WILLIAM STEERS, OF BRATTLEBOBOUGH, VERMONT.

EXTENSION-BIT.

SPECIFICATION forming part of Letters Patent No. 296,242, dated April 1, 1884-.

Application filed January 19, 1884.

T at whom it may concern.-

Be it known that I, WILLIAM STEERs, a citizen of the United States, residing at Brattleborough, in the county of Windham and State of Vermont, have invented certain new and useful Improvements in Extension-Bits, of which the following is a specification, reference being had therein to the accompanying drawings. 7

This invention relates to improvements in extension-bits for boring-tools; and it consists in the employment of an adjusting tangentscrew secured'in the stock, whereby the extension-blade can be easily, quickly, and accu- V which can be fitted to the brace-socket, or it may be used with a handle, like a common auger. The screw-thread on the gimlet-point is continued around the cylindrical part B, for the purpose of feeding the cutter B.

A is the extension-blade, of steel, having a cutting-edge, a, and lip a.

On the back of the extension-blade A is a dovetailed tongue, at, which fits into a corresponding groove, 22, in the stock A. Also, on the back of extension-blade A are threads 0, cut to suit the threads on a tangent-screw, D, which is made to turn in a corresponding non- No model.)

1 threaded groove across the stock A. A clamp,

O, is secured by a screw, D, so that when the extension-blade A is properly adjusted the clamp G is screwed down, but not so tightened as to prevent the sliding of the extension-blade when operated by the tangent-screw D. The dovetailed groove 1) in the stock A keeps the tongue a in the other edge of the extensionblade close to the stock, to prevent the blade from springing when in the act of cutting. In the end of tangent-screw D isa slot for ascrewdriver, so that by turning the tangent-screw D in either direction the extension-blade A is moved correspondingly. The tangent-screw D has a neck, e, and is secured by a pin, E, which passes through the stock and into the neck, to prevent the tangent-screw from being moved endwise when turned for the adjustment of the extension-blade, which is moved endwise by means of the threads on the back, and the nicest adjustment is obtained.

I claim- A center-bit stock having a continuation of the feeding-threads of the gimlet-point around the cylindrical part of the cutter, a tangentscrew secured by a neck and pin, a clamping device, and a dovetailed groove, in combination with an extension-blade having on its back a dovetailed ridge, and sore -threads to match the threads of the tangent-screw, substantially as and for the purpose described.

In testimony whereof I aflix my signature in presence of two witnesses.

WILLIAM STEERS.

Witnesses:

J. G. EDDY, H. J. BURNHAM. 

